Background: Synovial sarcoma is an uncommon soft tissue tumor of soft tissue, characterized by a specific SS18 rearrangement. It generally manifests as a lesion composed of monomorphic spindle cells and sometimes shows variable epithelial differentiation. Epithelial-type synovial sarcoma is rare, and synovial sarcoma with overwhelming neuroendocrine differentiation has not been reported previously.
Case presentation: Here, we present a case of a young man with an epithelial-type synovial sarcoma of the right leg that showed an overwhelming neuroendocrine differentiation. The diagnosis was confirmed by the detection of targeted fusion re-arrangement associated with synovial sarcoma.
Conclusions: This study emphasizes the importance of molecular approaches in modern soft tissue pathology. Detecting the expression of neuroendocrine antigens in synovial sarcoma is a pre-requisite to avoid misdiagnosis of metastatic neuroendocrine tumor, malignant peripheral nerve sheath tumor with glandular differentiation, and carcinosarcoma.
Keywords: Epithelial-type; Neuroendocrine differentiation; Synovial sarcoma.
© 2022. The Author(s).